USING XML IN THE NATIONAL GROUNDWATER DATABASE PROJECT

The national groundwater database is a project driven by the Geological Survey of Canada to provide groundwater related information from various providers in federal, provincial and private organisations. Groundwater data are hosted in a large spectrum of data models, formats or platforms, by more than 15 different organisations and, more importantly, are managed under various jurisdictions and accessibility constraints. One of the main goal of the project is to keep the data close to the producer and to keep away from creating any duplicate repository.

The technological solution to connect heterogeneous data providers is to set up a mechanism to translate on demand from these sources into a common, preferably neutral, data structure that can be handled by common software tools. Using this ‘lingua franca’ eliminates the need to convert between several possible structures and allow us to concentrate effort on a single conceptual model on which all participants agreed upon.

Virtually all emerging technologies to achieve such interoperability are now based on XML. Our department (Natural Resources Canada) is a strong advocate of using OGC standards, which rely essentially on XML. Some interesting geoscience initiatives propose XML encoding for some domains that groundwater utilises, such as XMML,NADM and UGLS (Geon) for geology and GML for spatial representation. Recent programming environment, communication protocols (WebServices with SOAP – also based on XML) and various off-the-shelf package open a new spectrum of possibilities that could not be envisioned a few years ago.

The current technological landscape is clearly lead by the XML bandwagon and an important component of the project will be to tie the pieces together. The first phase of the project was to perform a user requirement to define the basic parameters for a national groundwater database. Some ground work was done in 1991 between federal and provincial organisations to set up a common data standard, and the resulting standard is regarded as potential material for an XML schema for groundwater interchange. The second phase is to define an architecture that will address the issues raised in the user requirement.